On addition of one ml solution of 10% NaCl to 10 ml red gold sol in the presence of 0.0025 g of star — Surface Chemistry Chemistry Question

💡 Solution & Explanation

Gold number is the amount of protective colloid in mg added to 10 ml of standard gold sol to prevent coagulation. Amount of starch = 0.0025 g = 2.5 mg. Therefore, correct answer is B.